Cell identifier encoding and decoding methods and apparatus

Abstract

In an embodiment, a wireless communication system ( 100 , FIG. 1 ) includes one or more nodes ( 102 - 108 ) and one or more user equipments (UE) ( 110 ). A node may apply ( 502 , FIG. 5 ) a cell-specific spreading code to a cell identifier, which indicates an identity of a cell ( 113 , FIG. 1 ) serviced by the node. The node may insert ( 504 , FIG. 5 ), into a frame ( 200 , FIG. 2 ), at least one synchronization channel symbol, which corresponds to the spread cell identifier, and the node may transmit ( 506 , FIG. 5 ) the frame over an air interface. A UE may receive ( 702 , FIG. 7 ) a frame from the air interface. The UE may despread ( 708 ) the spread cell identifier, and acquire ( 712 ) a cell identifier corresponding to a particular cell.

1. A method for communication between a node and a user equipment within a multi-carrier network, wherein the node is configured to transmit at least one frame over an air interface, the method comprising:
 applying, by the node, a cell-specific spreading code to distinct parts of a cell identifier to produce multiple spread cell identifier parts, wherein the cell identifier indicates an identity of a cell that is serviced by the node, and wherein the cell-specific spreading code is derived from a subset of an orthogonal variable spreading factor spreading code sequence matrix; and 
 inserting multiple secondary synchronization channel symbols into the frame, wherein each of the multiple secondary synchronization channel symbols corresponds to one of the multiple spread cell identifier parts; 
 wherein responsive to receiving the frame, the user equipment despreads at least one of the multiple spread cell identifier parts, and determines a received signal quality based at least in part on the despread cell identifier parts. 
 
     
     
       2. The method of  claim 1 , wherein applying the spreading code comprises:
 applying the spreading code to the distinct parts of the cell identifier, wherein each of the distinct parts of the cell identifier is represented by a generalized chirp like index and a tone index. 
 
     
     
       3. The method of  claim 1 , wherein applying the spreading code comprises:
 applying a substantially orthogonal spreading code to the distinct parts of the cell identifier. 
 
     
     
       4. The method of  claim 1 , wherein applying the spreading code comprises:
 applying a spreading code that includes seven elements. 
 
     
     
       5. The method of  claim 1 , wherein inserting the multiple secondary synchronization channel symbols comprises:
 inserting, into the frame, a first secondary synchronization channel symbol and a second secondary synchronization channel symbol, wherein a first part of the cell identifier can be encoded into the first secondary synchronization channel symbol, and a second part of the cell identifier can be encoded into the second secondary synchronization channel symbol; and 
 wherein the method further comprises inserting, into the frame, a first primary synchronization channel symbol and a second primary synchronization channel symbol, wherein the first primary synchronization channel symbol can be used to decode the first secondary synchronization channel symbol, and the second primary synchronization channel symbol can be used to decode the second secondary synchronization channel symbol. 
 
     
     
       6. The method of  claim 1 , further comprising:
 transmitting the frame over an air interface. 
 
     
     
       7. The method of  claim 6 , wherein transmitting the frame comprises:
 transmitting the frame synchronously with at least one other node. 
 
     
     
       8. The method of  claim 6 , further comprising:
 transmitting the frame asynchronously from at least one other node. 
 
     
     
       9. A method for communication between a node and a user equipment within a multi-carrier network, wherein the node is configured to transmit at least one frame over an air interface, the method comprising:
 receiving multiple secondary synchronization channel symbols, each of which corresponds to a distinct part of a cell identifier to which a cell-specific spreading code has been applied, wherein the cell-specific spreading code is derived from a subset of an orthogonal variable spreading factor spreading code sequence matrix; 
 despreading the multiple secondary synchronization channel symbols using one or more cell-specific spreading codes to produce a despreading operation result, comprising one or more received signal quality measurements corresponding to each of the one or more cell-specific spreading codes; and 
 acquiring a cell identifier based on the despreading operation result, wherein the cell identifier indicates an identity of a cell serviced by a node that transmitted the highest received signal quality measurement. 
 
     
     
       10. The method of  claim 9 , wherein despreading the multiple secondary synchronization channel symbols comprises:
 despreading the multiple secondary synchronization channel symbols multiple times by applying, to the multiple secondary synchronization channel symbols, multiple cell-specific spreading codes assigned to multiple system nodes, to produce a despreading operation result that includes signal-to-interference plus noise ratio values associated with each of the multiple system nodes. 
 
     
     
       11. The method of  claim 10 , wherein applying the multiple cell-specific spreading codes comprises:
 applying multiple substantially orthogonal spreading codes to the at least one secondary synchronization channel symbol. 
 
     
     
       12. The method of  claim 10 , wherein applying the multiple cell-specific spreading codes comprises:
 applying multiple cell-specific spreading codes, each of which includes seven elements. 
 
     
     
       13. The method of  claim 9 , further comprising:
 processing at least one primary synchronization channel symbol to perform coarse timing adjustment and carrier frequency offset correction prior to despreading the at least one secondary synchronization channel symbols. 
 
     
     
       14. The method of  claim 9 , further comprising:
 registering with the node associated with the cell identifier. 
 
     
     
       15. The method of  claim 9 , further comprising:
 handing off to the node associated with the cell identifier. 
 
     
     
       16. An apparatus comprising:
 one or more integrated circuits adapted to apply a cell-specific spreading code to distinct parts of a cell identifier to produce multiple spread cell identifier parts, wherein the cell identifier indicates an identity of a cell serviced by a node of a multi-carrier network, and wherein the cell-specific spreading code is derived from a subset of an orthogonal variable spreading factor spreading code sequence matrix, and wherein the one or more integrated circuits are further adapted to insert multiple secondary synchronization channel symbols into a frame, wherein each of the multiple secondary synchronization channel symbols corresponds to one of the multiple spread cell identifier parts; and 
 wherein the multiple spread cell identifiers are configured to enable a receiver to determine a received signal quality associated with the cell identifier among a plurality of received cell identifiers. 
 
     
     
       17. The apparatus of  claim 16 , wherein the apparatus forms a portion of the node, and the apparatus further comprises:
 one or more air interface subsystems, operably coupled to the one or more integrated circuits, to transmit the frame synchronously over an air interface. 
 
     
     
       18. The apparatus of  claim 16 , wherein the apparatus forms a portion of the node, and the apparatus further comprises:
 one or more air interface subsystems, operably coupled to the one or more integrated circuits, to transmit the frame asynchronously over an air interface. 
 
     
     
       19. User apparatus for use within a multi-carrier network, the user apparatus comprising:
 an air interface apparatus configured to receive a frame from a node of the network, the frame comprising multiple spread cell identifier parts obtained by the application of a cell-specific spreading code associated with a subset of a spreading code sequence matrix to distinct parts of a cell identifier, the cell identifier indicating an identity of a cell that is serviced by the node, the frame further comprising multiple secondary synchronization channel symbols each corresponding to one of the multiple spread cell identifier parts; and 
 apparatus configured to, responsive to receiving the frame, despread at least one of the multiple spread cell identifier parts, and determine a received signal quality based at least in part on the despread cell identifier parts. 
 
     
     
       20. An apparatus comprising:
 one or more integrated circuits adapted to apply a cell-specific spreading code to distinct parts of a cell identifier for a cell serviced by a node of a network, to produce multiple spread cell identifier parts, the cell-specific spreading code derived from a subset of a spreading code matrix, the one or more integrated circuits further being configured to insert multiple secondary synchronization channel symbols into the frame, each of the multiple secondary synchronization channel symbols corresponding to one of the multiple spread cell identifier parts; and 
 wherein the multiple spread cell identifiers are configured to enable a receiver to determine a received signal quality associated with the cell identifier from among a plurality of received cell identifiers. 
 
     
     
       21. User apparatus configured for communication with a wireless network, the apparatus comprising:
 air interface apparatus configured to receive one or more frames each comprising multiple spread cell identifier parts, the multiple spread cell identifier parts having been generated using a cell-specific spreading code applied to a cell identifier for a cell of the network, the cell-specific spreading code having been derived from a subset of a spreading code matrix, the one or more frames further comprising multiple secondary synchronization channel symbols each corresponding to one of the multiple spread cell identifier parts; and 
 apparatus configured to utilize the multiple spread cell identifiers to determine a received signal quality associated with the cell identifier from among a plurality of received cell identifiers.